[数据结构与算法]leetcode-225. 用队列实现栈

一、题目

二、思路

三、代码

class MyStack {
public:
    queue<int>s,t;
    MyStack() {

    }
    
    void push(int x) {
        t.push(x);
        while(!s.empty()){
            t.push(s.front());
            s.pop();
        }
        swap(s,t);       
    }
    
    int pop() {        
        int x=s.front();
        s.pop();
        return x;
    }
    
    int top() {
        return s.front();
    }
    
    bool empty() {
        if(s.empty()){
            return true;
        }
        return false;
    }
};

/**
 * Your MyStack object will be instantiated and called as such:
 * MyStack* obj = new MyStack();
 * obj->push(x);
 * int param_2 = obj->pop();
 * int param_3 = obj->top();
 * bool param_4 = obj->empty();
 */